I was revisiting some old memories and reading up on the Space Shuttle while working on my current project, and remembered something: There was apparently a possibility of Big Bird flying on the Challenger instead of Christa McAuliffe.
What would be the effects on the kids of America if they had seen Big Bird walk into the shuttle, wave--and then seen the ship blow up? I was in college at the time, and the Challenger had a major impact in me.
Grim thinking, but the sort of thing that can have major cultural impacts.